As Nathan says, a majority of American workers would likely join a union if given the option. Most aren't given the option. ARW argues that major changes to labor law are needed to change this—including establishing "card checks" as a process for union organization, whereby a workplace would be unionized if a majority of workers simply signed a card, plus much tougher penalties for any employer that violated labor laws. But there's also something of a catch-22 here: Effective pro-labor legislation will be very difficult to pass in Congress without a strong labor movement agitating for it, but it's hard for the labor movement to become strong so long as the law is biased against unions.

So what to do, what to do? One of my favorite "out of the box" labor proposal comes from Joel Rogers and Richard Freeman, who have argued that "open-source unionism" is the way forward:

[Right now,] workers typically become union members only when unions gain majority support at a particular workplace. This makes the union the exclusive representative of those workers for purposes of collective bargaining. Getting to majority status… is a struggle. The law barely punishes employers who violate it, and the success of the union drive is typically determined by the level of employer resistance. Unions usually abandon workers who are unsuccessful in their fight to achieve majority status, and they are uninterested in workers who have no plausible near-term chance of such success.

Under open-source unionism, by contrast, unions would welcome members even before they achieved majority status, and stick with them as they fought for it--maybe for a very long time. These "pre-majority" workers would presumably pay reduced dues in the absence of the benefits of collective bargaining, but would otherwise be normal union members. They would gain some of the bread-and-butter benefits of traditional unionism--advice and support on their legal rights, bargaining over wages and working conditions if feasible, protection of pension holdings, political representation, career guidance, access to training and so on.

And even in minority positions, they might gain a collective contract for union members, or grow to the point of being able to force a wall-to-wall agreement for all workers in the unit. … Joining the labor movement would be something you did for a long time, not just an organizational relationship you entered into with a third party upon taking some particular job, to expire when that job expired or changed.

I don't really know what the upsides and downsides of this proposal are—it looks like all upside to me, but it's certainly worth debating, rather than waiting around hoping that pro-labor Democrats will ever regain power and fiddle with the law.